Pork Chop's Commute

RAY: The inspiration for this puzzler was sent in by Warner Grenady. Of course, I had to add some obfuscatory details, and I personalized it a little bit. Some of you might remember our nephew Matt, whom we called "Pork Chop Boy," because his social life was so bad, he had to tie a pork chop around his neck even to get the dog to play with him.

Anyway, some years ago he dislocated his right shoulder playing chess. It was "strip chess" actually, but, we don't have to go into that. His shoulder hurt so much that he couldn't move the shifter on his automatic transmission. He tried to reach over and shift with the other hand, but twisting in the seat hurt even more. But, Pork Chop Boy needed to drive to work every day, and he didn't have any way to get there.

Tommy said, "No problem. You can use my car."

He did, and he had no problem driving Tommy's car to work-- yet, he couldn't shift his own automatic transmission car. The question is, which one of Tommy's jalopies did Matt use to get to work, and why?